[0001] The invention relates to cosmetic compositions containing organic sunscreens which
are stabilized against degradation by incorporation of 4-substituted resorcinol derivatives
in the compositions.
[0002] Certain organic substances, known as sunscreens, whose molecules absorb the harmful
ultraviolet rays, are widely used in cosmetic compositions to protect human skin against
the damaging effects of sunlight. Sunscreens are described in many publications, including
Nicoll et al., U.S. Patent No. 5,188,831 and
Dobrowski et al., U.S. Patent No. 5,961,961. The effectiveness of sunscreens is measured in terms of a property known as the
Sun Protection Factor (SPF), as is well know to one skilled in the art.
[0003] The ideal sunscreen should be sufficiently chemically and physically stable so as
to provide an acceptable shelf life upon storage. It is particularly desirable that
the preparation should retain its protective effect over a prolonged period after
application. Thus, the active agent when present on the skin must be resistant to
chemical or photodegradation, to absorption through the skin, and to removal by perspiration,
skin oil, or water.
[0004] Sunscreen agents in the order of decreasing effectiveness may be categorized as either
highly chromophoric monomeric organic compounds, inorganic compounds and minimally
chromophoric polymeric organic solids.
[0006] Chromophoric monomeric, organic compounds are subject to certain problems. Organic
sunscreens, when incorporated in personal care compositions or when deposited on skin,
lose their sunscreen properties and may change character with time, due to many factors.
[0007] Among many reasons for degradation, one factor responsible for loss of sun screen
factor (SPF) or change in character is that organic sunscreens are oxidatively, or
photooxidatively, unstable. Instability is an undesirable characteristic in organic
sunscreens. There is a need, therefore, for an agent that will stabilize organic sunscreens
against degradation. In particular, there is a need for an agent that will prevent
the oxidation or photooxidation of organic sunscreens.
[0008] The applicants have now discovered that inclusion of 4-substituted resorcinol derivatives
in combination with organic sunscreens in personal care compositions provides oxidative
or photooxidative stability to the organic sunscreens. Accordingly, the present invention
provides a cosmetic composition comprising:
- a. about 0.01 wt.% to about 20 wt.% of an organic sunscreen,
- b. about 0.0001 wt.% to about 50 wt.% of a 4-substituted resorcinol derivative of
the general formula I
wherein each R1 and R2, independently, represents a hydrogen atom, -CO-R, -COO-R, CONHR; where R represents
saturated or unsaturated, linear, branched or cyclic C1 - C18 hydrocarbon groups; and
R3 represents (1) an alkyl group, having from 1 to 18 carbon atoms, preferably having
from 2 to 12 carbon atoms, with or without substitution of one or more hydrogen atoms
of a linear alkyl group with a methyl or ethyl group; e.g., R3 constitutes linear or branched chain alkyls, or (2) a group of the general formula
(II)
wherein X is hydrogen; OR1, wherein R1 represents hydrogen, (C1-C6)alkyl or aryl-(C1-C6)alkyl; OCOR2 wherein R2 represents (C1-C6)alkyl, aryl-(C1-C6)alkyl or phenyl; halogen; (C1-C6)alkyl; aryl-(C1-C6)alkyl, or aryl-(C1-C6)alkyl; or NHR1 wherein R1 is defined as above;
wherein n is 0 to 3 such that the structure of general formula II is a 5, 6, 7 or
8 membered ring;
wherein the dashed line indicates an optional double bond;
and
- c. a cosmetically acceptable vehicle.
[0009] The inventive compositions are aesthetically pleasing and have improved oxidative
or photooxidative stability, which provides longer lasting effect after application
to the skin as well as degradation upon storage.
[0010] As used herein, the term "cosmetic composition" is intended to describe compositions
for topical application to human skin, including leave-on and wash-off products.
[0011] The term "skin" as used herein includes the skin on the face, neck, chest, back,
arms, axillae, hands, legs, and scalp.
[0012] The term "inhibit" as it relates to oxidation of sunscreens is intended to describe
a decrease in oxidation of sunscreens by at least a certain amount, and at most completely.
[0013] Except in the examples, or where otherwise explicitly indicated, all numbers in this
description indicating amounts of material or conditions of reaction, physical properties
of materials and/or use are to be understood as modified by the word "about". All
amounts are by weight of the composition, unless otherwise specified.
[0014] For the avoidance of doubt the word "comprising" is intended to mean including but
not necessarily consisting of or composed of. In other words the listed steps or options
need not be exhaustive.
[0015] The invention is concerned with a cosmetic composition employing 4-substituted resorcinol
derivatives to inhibit the degradation of organic sunscreens present therein. Preferably,
in the cosmetic compositions of the present invention, 4-substituted resorcinol derivatives
are used to stabilize organic sunscreens against oxidation or photooxidation. Depending
upon the nature of the cosmetic composition, other skin benefit materials and/or cosmetic
adjuncts can optionally be present, and the 4-substituted resorcinol derivatives may
also serve to provide a skin benefit in addition to having a stabilizing function
for the sunscreens.
[0016] The inventive cosmetic compositions include an organic sunscreen to provide protection
from the harmful effects of excessive exposure to sunlight. Organic sunscreens for
purposes of the inventive compositions are organic sunscreen agents having at least
one chromophoric group absorbing within the ultraviolet range of from 290 to 400 nm.
Chromophoric organic sunscreen agents may be divided into the following categories
(with specific examples), including: p-Aminobenzoic acid, its salts and its derivatives
(ethyl, isobutyl, glyceryl esters; p-dimethylaminobenzoic acid); Anthranilates (o-aminobenzoates;
methyl, menthyl, phenyl, benzyl, phenylethyl, linalyl, terpinyl, and cyclohexenyl
esters); Salicylates (octyl, amyl, phenyl, benzyl, menthyl, glyceryl, and dipropyleneglycol
esters); Cinnamic acid derivatives (menthyl and benzyl esters, .alpha.- phenyl cinnamonitrile;
butyl cinnamoyl pyruvate); Dihydroxycinnamic acid derivatives (umbelliferone, methylumbelliferone,
methylaceto- umbelliferone); Trihydroxycinnamic acid derivatives (esculetin, methylesculetin,
daphnetin, and the glucosides, esculin and daphnin); Hydrocarbons (diphenylbutadiene,
stilbene); Dibenzalacetone and benzalacetophenone; Naphtholsulfonates (sodium salts
of 2-naphthol-3,6- disulfonic and of 2-naphthol-6,8-disulfonic acids); Dihydroxy-naphthoic
acid and its salts; o- and p-Hydroxybiphenyldisulfonates; Coumarin derivatives (7-hydroxy,
7-methyl, 3-phenyl); Diazoles (2-acetyl-3-bromoindazole, phenyl benzoxazole, methyl
naphthoxazole, various aryl benzothiazoles); Quinine salts (bisulfate, sulfate, chloride,
oleate, and tannate); Quinoline derivatives (8-hydroxyquinoline salts, 2- phenylquinoline);
Hydroxy- or methoxy-substituted benzophenones; Uric and vilouric acids; Tannic acid
and its derivatives (e.g., hexaethylether); (Butyl carbityl) (6-propyl piperonyl)
ether; Hydroquinone; Benzophenones (Oxybenzone, Sulisobenzone, Dioxybenzone, Benzoresorcinol,
2,2 ', 4,4'-Tetrahydroxybenzophenone, 2,2'-Dihydroxy-4, 4'-dimethoxybenzophenone,
Octabenzone; 4-Isopropyldibenzoylmethane; Butylmethoxydibenzoylmethane; Etocrylene;
and 4-isopropyl- dibenzoylmethane).
[0017] Particularly useful are: 2-ethylhexyl p-methoxycinnamate, 4,4'-t- butyl methoxydibenzoylmethane,
2-hydroxy-4-methoxybenzophenone, octyldimethyl p-aminobenzoic acid, digalloyltrioleate,
2,2-dihydroxy-4-methoxybenzophenone, ethyl 4-[bis(hydroxypropyl)]aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate,
2-ethylhexylsalicylate, glyceryl p-aminobenzoate, 3,3,5-trimethylcyclohexylsalicylate,
methylanthranilate, p-dimethylaminobenzoic acid or aminobenzoate, 2- ethylhexyl p-dimethylaminobenzoate,
2-phenylbenzimidazole-5-sulfonic acid, 2-(p-dimethylaminophenyl)-5-sulfoniobenzoxazoic
acid and mixtures thereof.
[0018] Suitable commercially available organic sunscreen agents are those identified under
the following table.
TABLE 1
CTFA Name |
Trade Name |
Supplier |
Benzophenone-3 |
UVINUL M-40 |
BASF Chemical Co. |
Benzophenone-4 |
UVINUL MS-40 |
BASF Chemical Co. |
Benzophenone-8 |
SPECRA-SORB UV-24 |
American Cyanamide |
DEA Methoxycinnamate |
BERNEL HYDRO |
Bernel Chemical |
Ethyl dihydroxypropyl-PABA |
AMERSCREEN P |
Amerchol Corp. |
Glyceryl PABA |
NIPA G.M.P.A. |
Nipa Labs. |
Homosalate |
KEMESTER HMS |
Hunko Chemical |
Methyl anthranilate |
SUNAROME UVA |
Felton Worldwide |
Octocrylene |
UVINUL N-539 |
BASF Chemical Co. |
Octyl dimethyl PABA |
AMERSCOL |
Amerchol Corp. |
Octyl methoxycinnamate |
PARSOL MCX |
Bernel Chemical |
Octyl salicylate |
SUNAROME WMO |
Felton Worldwide |
PABA |
PABA |
National Starch |
2-Phenylbenzimidazole-5-sulphonic acid |
EUSOLEX 232 |
EM Industries |
TEA salicylate |
SUNAROME W |
Felton Worldwide |
3-(4-methylbenzylidene) -camphor |
EUSOLEX 6300 |
EM Industries |
Benzophenone-1 |
UVINUL 400 |
BASF Chemical Co. |
Benzophenone-2 |
UVINUL D-50 |
BASF Chemical Co. |
Benzophenone-6 |
UVINUL D-49 |
BASF Chemical Co. |
Benzophenone-12 |
UVINUL 408 |
BASF Chemical Co. |
4-Isopropyl dibenzoyl methane |
EUSOLEX 8020 |
EM Industries |
Butyl methoxy dibenzoyl methane |
PARSOL 1789 |
Givaudan Corp. |
Etocrylene |
UVINUL N-35 |
BASF Chemical Co. |
[0019] The amount of the organic sunscreens in the personal care composition is generally
in the range of about 0.01% to about 20%, preferably in the range of about 0.1% to
about 10%.
[0020] Preferred organic sunscreens are Parsol MCX and Parsol 1789, due to their effectiveness
and commercial availability.
[0021] Suitable 4-substituted resorcinol derivatives are known compounds and can be readily
obtained, for example, by a method wherein a saturated carboxylic acid and resorcinol
are condensed in the presence of zinc chloride and the resultant condensate is reduced
with zinc amalgam/hydrochloric acid (
Lille. J. Bitter, LA. Peiner. V, Tr. Nauch-Issled. Inst. slantsev 1969, No. 18, 127), or by a method wherein resorcinol and a corresponding alkyl alcohol are reacted
in the presence of an alumina catalyst at a high temperature of from 200 to 400°C
(British Patent No.
1,581,428).
[0022] The inventive compositions generally contain about 0.01% to about 20% of organic
sunscreens and about 0.000001% to about 50% of 4-substituted resorcinols. The particular
advantage of the inventive compositions is that organic sunscreens can be stabilized
by 4-substituted resorcinols against oxidation or photo-oxidation.
[0023] The stability of the inventive compositions is achieved by the use of an antioxidant
agent which comprises, as an effective component, a resorcinol derivative of the following
formula (I):
[0024] Each R
1 and R
2, independently, represents a hydrogen atom, - CO-R (acyl group), -COO-R, CONHR groups;
where R represents saturated or unsaturated linear, branched or cyclic C
1-C
18 hydrocarbon. In a preferred embodiment, each or both R
1 and/or R
2 represents hydrogen. In a more preferred embodiment, both R
1 and R
2 represent hydrogen.
[0025] R
3 represents:
- (1) an alkyl group, preferably having from 1 to 18 carbon atoms, preferably 2 to 12
carbon atoms, with or without substitution of one or more hydrogen atoms of a linear
alkyl group with a methyl or ethyl group; e.g., R3 constitutes linear or branched chain alkyls,
or
- (2)a group of the general formula formula (II)
wherein X is hydrogen; OR1, wherein R1 represents hydrogen, (C1 - C6)alkyl or aryl-(C1-C6)alkyl; OCOR2 wherein R2 represents (C1-C6)alkyl, aryl-(C1-C6)alkyl or phenyl; halogen; (C1-C6)alkyl; aryl-(C1-C6)alkyl, or aryl-(C1-C6)alkyl; or NHR1 wherein R1 is defined as above;
wherein n is 0 to 3 such that the structure of general formula II is a 5, 6, 7 or
8 membered ring; and
wherein the dashed line indicates an optional double bond.
[0026] In the above formula (1), the unsubstituted linear alkyl group represented by R and
preferably having from 2 to 12 carbon atoms may include an ethyl group, a propyl group,
a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl
group, a decyl group, an undecyl group and a dodecyl group. These linear alkyl groups
may be substituted with a methyl or ethyl group at one or more hydrogen atoms thereof.
Specific examples of the substituted alkyl group include an isopropyl group, an isobutyl
group, an isoamyl group, or a 2-methylhexyl group. Preferred alkyl groups are those
where R is an ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl group. The most
preferable alkyl resorcinols are those where R is an ethyl, a butyl or a hexyl group.
[0027] In the above formula (I) where R3 has the general formula II, the compounds are referred
to herein as 4-cyclo-substituted resorcinols of general formula III
X is hydrogen; OR1, wherein R1 represents hydrogen, (C1 - C6)alkyl or aryl-(C1-C6)alkyl; OCOR2 wherein R2 represents (C1-C6)alkyl, aryl-(C1-C6)alkyl or phenyl; halogen; (C1-C6)alkyl; aryl-(C1-C6)alkyl, or aryl-(C1-C6)alkyl; or NHR1 wherein R1 is defined as above;
n is 0 to 3; and
the dashed line indicates an optional double bond at that position.
[0028] Examples of more specific embodiments of the 4-cyclo-substituted resorcinols include:
- (a) compounds of the formula (III) wherein a single bond connects the two carbon atoms
at the dashed line;
- (b) compounds of the formula (III) wherein n is one;
- (c) compounds of the formula (III) wherein X is hydrogen;
- (d) compounds of the formula (III) wherein X is hydrogen, methyl or ethyl;
- (e) compounds of the formula (III) wherein n is zero;
- (f) compounds of the formula (III) wherein n is two; and
- (g) compounds of the formula (III) wherein X is benzyloxy.
[0029] Preferred compounds of formula (III) are 4-cyclopentylresorcinol, 4-cyclohexyl resorcinol,
4-cycloheptyl resorcinol, and 4-cyclooctyl resorcinol. Most preferred compounds of
formula (III) are 4-cyclohexylresorcinol and 4-cyclopentylresorcinol.
[0030] An amount of 4-substituted resorcinol derivative effective to inhibit the oxidation
of organic sunscreens may be determined by experimentation. The organic sunscreens
and 4-substituted resorcinol derivatives are present in the composition in a weight
ratio of about 1:1000 to 1000:1, preferably 1:100 to 100:1, more preferably 1:1 to
1:100.
[0031] The amount of the resorcinol derivative is preferably in the range of about 0.00001%
to about 10%, more preferably about 0.001% to 7%, most preferably from 0.01% to about
5% of the total amount of a cosmetic composition.
[0032] Preferred cosmetic compositions are those suitable for the application to human skin,
which optionally but preferably include a skin benefit agent.
[0033] Suitable skin benefit agents include anti-aging, wrinkle-reducing, skin whitening,
anti-acne, and sebum reduction agents. Examples of these include alpha-hydroxy acids
and esters, beta-hydroxy acids and ester, polyhydroxy acids and esters, kojic acid
and esters, ferulic acid and ferulate derivatives, vanillic acid and esters, dioic
acids (such as sebacid and azoleic acids) and esters, retinol, retinal, retinyl esters,
hydroquinone, t-butyl hydroquinone, mulberry extract, licorice extract, and resorcinol
derivatives other than the 4-substituted resorcinol derivatives discussed hereinabove
(thereby serving a dual function of providing oxidative stabilization of organic sunscreens
and of providing a skin benefit, such as lightening for example).
[0034] The skin benefit agent together with the organic sunscreen compound and resorcinol
derivative of the invention is usually used along with a cosmetic base. Suitable cosmetically
acceptable carriers are well known to one skilled in the art. The cosmetic bases may
be any bases which are ordinarily used for skin benefit agents, and are thus not critical.
Specific preparations of the cosmetics to which the skin benefit agents of the invention
is applicable include creams, ointments, emulsions, lotions, oils, packs and nonwoven
wipes. Cream bases are, for example, beeswax, cetyl alcohol, stearic acid, glycerine,
propylene glycol, propylene glycol monostearate, polyoxyethylene cetyl ether and the
like. Lotion bases include, for example, oleyl alcohol, ethanol, propylene glycol,
glycerine, lauryl ether, sorbitan monolaurate and the like.
[0035] The cosmetically acceptable vehicle may act as a dilutant, dispersant or carrier
for the skin benefit ingredients in the composition, so as to facilitate their distribution
when the composition is applied to the skin.
[0036] The vehicle may be aqueous, anhydrous or an emulsion. Preferably, the compositions
are aqueous or an emulsion, especially water-in-oil or oil-in-water emulsion, preferentially
oil in water emulsion. Water when present will be in amounts which may range from
5% to 99%, preferably from 20% to 70%, optimally between 40% and 70% by weight.
[0037] Besides water, relatively volatile solvents may also serve as carriers within compositions
of the present invention. Most preferred are monohydric C
1-C
3 alkanols. These include ethyl alcohol, methyl alcohol and isopropyl alcohol. The
amount of monohydric alkanol may range from 1% to 70%, preferably from 10% to 50%,
optimally between 15% to 40% by weight.
[0038] Emollient materials may also serve as cosmetically acceptable carriers. These may
be in the form of silicone oils and synthetic esters. Amounts of the emollients may
range anywhere from 0.1% to 50%, preferably between 1% and 20% by weight.
[0039] Silicone oils may be divided into the volatile and non-volatile variety. The term
"volatile" as used herein refers to those materials which have a measurable vapor
pressure at ambient temperature. Volatile silicone oils are preferably chosen from
cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to
5, silicon atoms. Linear volatile silicone materials generally have viscosities less
than about 5 centistokes at 25°C while cyclic materials typically have viscosities
of less than about 10 centistokes. Nonvolatile silicone oils useful as an emollient
material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane
copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include,
for example, polydimethyl siloxanes with viscosities of from about 5 to about 25 million
centistokes at 25°C. Among the preferred non-volatile emollients useful in the present
compositions are the polydimethyl siloxanes having viscosities from about 10 to about
400 centistokes at 25°C.
[0040] Among the suitable ester emollients are:
- (1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples
thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate,
oleyl stearate, and oleyl oleate;
- (2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols;
- (3) Polyhydric alcohol esters, including ethylene glycol mono and di-fatty acid esters,
diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono-
and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene
glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene
glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty
esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene
glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters,
and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol
esters;
- (4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and
arachidyl behenate; and
- (5) Sterol esters, of which cholesterol fatty acid esters are examples.
[0041] Fatty acids having from 10 to 30 carbon atoms may also be included as cosmetically
acceptable carriers for compositions of this invention. Illustrative of this category
are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic,
linoleic, ricinoleic, arachidic, behenic and erucic acids.
[0042] Humectants of the polyhydric alcohol-type may also be employed as cosmetically acceptable
carriers in compositions of this invention. The humectant aids in increasing the effectiveness
of the emollient, reduces skin dryness and improves skin feel. Typical polyhydric
alcohols include glycerol, polyalkylene glycols and more preferably alkylene polyols
and their derivatives, including propylene glycol, dipropylene glycol, polypropylene
glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol,
hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated
glycerol and mixtures thereof. The amount of humectant may range anywhere from 0.5%
to 30%, preferably between 1% and 15% by weight of the composition.
[0043] Thickeners may also be utilized as part of the cosmetically acceptable carrier of
compositions according to the present invention. Typical thickeners include crosslinked
acrylates (e.g. Carbopol 982), hydrophobically-modified acrylates (e.g. Carbopol 1382),
cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium
carboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl
cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for
the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations
of these gums. Amounts of the thickener may range from 0.0001% to 5%, usually from
0.001% to 1%, optimally from 0.01% to 0.5% by weight.
[0044] Collectively the water, solvents, silicones, esters, fatty acids, humectants and/or
thickeners will constitute the cosmetically acceptable carrier in amounts from 1%
to 99.9%, preferably from 80% to 99% by weight.
[0045] An oil or oily material may be present, together with an emulsifier to provide either
a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average
hydrophilic-lipophilic balance (HLB) of the emulsifier employed.
[0046] Surfactants may also be present in cosmetic compositions of the present invention.
For leave-on products, total concentration of the surfactant will range from 0.1%
to 40%, preferably from 1% to 20%, optimally from 1% to 5% by weight of the composition.
For wash-off products, such as cleansers and soap, total concentration of surfactant
will range at about 1% to about 90%. The surfactant may be selected from the group
consisting of anionic, nonionic, cationic and amphoteric actives.
[0047] Particularly preferred nonionic surfactants are those with a C
10-C
20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide
or propylene oxide per mole of hydrophobe; C
2-C
10 alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di-
fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and
di- C
8-C
20 fatty acids; block copolymers (ethylene oxide/propylene oxide); and polyoxyethylene
sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty
amides (e.g. methyl gluconamides) are also suitable nonionic surfactants.
[0048] Preferred anionic surfactants include soap, alkyl ether sulfate and sulfonates, alkyl
sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates,
C
8-C
20 acyl isethionates, acyl glutamates, C
8-C
20 alkyl ether phosphates and combinations thereof.
[0049] The inventive cosmetic compositions optionally contain a lathering surfactant. By
a "lathering surfactant" is meant a surfactant which, when combined with water and
mechanically agitated, generates a foam or lather. Preferably, the lathering surfactant
should be mild, meaning that it must provide sufficient cleansing or detergent benefits
but not overly dry the skin, and yet meet the lathering criteria described above.
The cosmetic compositions of the present invention may contain a lathering surfactant
in a concentration of about 0.01% to about 50%.
[0050] In the cosmetic compositions of the invention, there may be added various other optional
components such as plasticizers, elastomers, calamine, pigments, antioxidants, chelating
agents, and perfumes, as well as additional sunscreens such UV diffusing agents, typical
of which is finely divided titanium oxide and zinc oxide.
[0051] Other adjunct minor components may also be incorporated into the cosmetic compositions.
These ingredients may include coloring agents, opacifiers, and perfumes. Amounts of
these other adjunct minor components may range anywhere from 0.001% up to 20% by weight
of the composition.
[0052] The composition according to the invention is intended primarily as a personal care
product for topical application to human skin, as well as to protect exposed skin
from the harmful effects of excessive exposure to sunlight.
[0053] In use, a small quantity of the composition, for example about 0.1 to about 5 ml,
is applied to exposed areas of the skin, from a suitable container or applicator and,
if necessary, it is then spread over and/or rubbed into the skin using the hand or
fingers or a suitable device.
[0054] The cosmetic composition of the invention can be formulated as a lotion having a
viscosity of from 4,000 to 10,000 mPas, a fluid cream having a viscosity of from 10,000
to 20, 000 mPas or a cream having a viscosity of from 20,000 to 100,000 mPas or above,
all measured at 25°C. The composition can be packaged in a suitable container to suit
its viscosity and intended use by the consumer. For example, a lotion or fluid cream
can be packaged in a bottle or a roll-ball applicator or a propellant-driven aerosol
device or a container fitted with a pump suitable for finger operation. When the composition
is a cream, it can simply be stored in a non-deformable bottle or squeeze container,
such as a tube or a lidded jar.
[0055] The invention accordingly also provides a closed container containing a cosmetically
acceptable composition as herein defined.
[0056] The following specific examples further illustrate the invention, but the invention
is not limited thereto. In all examples, organic sunscreens were obtained from Givaudan
Corp.
EXAMPLES
Examples 1-8
[0057] A set of compositions within the scope of the present invention were prepared and
listed in the Table below. The composition is in weight per cent.
TABLE 2
Ingredient Trade and CTFA Name |
Phase |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 Base |
Stearic acid |
A |
14.9 |
14.9 |
12.9 |
17.9 |
14.0 |
14.0 |
14.0 |
14.0 |
Sodium cetearyl sulfate |
A |
1.0 |
1.0 |
1.5 |
1.5 |
1 |
1 |
1 |
1 |
Myrj 59 |
A |
2.0 |
1.5 |
2 |
2 |
2 |
2 |
2 |
2 |
Span 60 |
A |
2.0 |
1.5 |
2 |
2 |
2 |
2 |
2 |
2 |
Propyl paraben |
A |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
BHT |
A |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
Dimethicone |
A |
|
0.50 |
0.75 |
|
0.75 |
0.75 |
0.75 |
0.75 |
Water |
B |
BAL* |
BAL |
BAL |
BAL |
BAL |
BAL |
BAL |
BAL |
EDTA |
B |
0.04 |
0.04 |
0.04 |
0.04 |
0.04 |
0.04 |
0.04 |
0.04 |
Pemulen TR 2 |
B |
|
0.10 |
0.05 |
|
0.05 |
0.05 |
0.05 |
0.05 |
Methyl paraben |
B |
0.15 |
0.15 |
0.15 |
0.15 |
0.15 |
0.15 |
0.15 |
0.15 |
Parsol MCX (organic sunscreen) |
C |
0.75 |
1.25 |
1 |
1 |
0.75 |
0.75 |
0.75 |
0.75 |
Parsol 1789 (organic sunscreen) |
C |
0.40 |
|
0.4 |
0.4 |
0.4 |
0.4 |
0.4 |
0.4 |
Micronized Titanium oxide |
C |
|
|
|
|
0.2 |
0.2 |
0.2 |
0.2 |
Propylene glycol |
D |
|
|
|
|
8 |
8 |
8 |
8 |
Transcutol |
D |
|
|
|
|
4 |
4 |
4 |
4 |
4-butyl resorcinol |
D |
0.05 |
2.0 |
2.0 |
3.5 |
|
|
|
|
4-ethyl resorcinol |
D |
|
|
|
|
2.5 |
|
|
|
4-hexyl resorcinol |
D |
|
|
|
|
|
3.51 |
|
|
4-hexyl resorcinol diacetate |
D |
|
|
|
|
|
|
5.0 |
|
[0058] The compositions of Examples 1-7 in the Table above, as well as Example 8 which is
the base composition without addition of any resorcinol derivative, were prepared
in the following fashion. Phase A is heated at 75°C. Phase B is heated to 75°C in
a container separate from that of Phase A. Thereafter the phases are combined with
mixing with heat being turned off. Phase C was premixed and warmed then added immediately
after phase A and B mixed. Phase D is pre-dissolved and added into the main pot at
60°C. The mixture is cooled until 40°C and then packed.
Example 9
[0059] The photo-stability of organic sunscreens in various cosmetic compositions was measured
in the presence and absence of resorcinol derivatives. Examples 5 to 8 in the Table
above were tested for this purpose. The resorcinol derivatives in these examples were
tested at equivalent molar concentrations in the formulations (18.09mM). The photo-stability
of a UVA organic sunscreen, Parsol 1789, in these compositions was assessed by monitoring
the loss of Monochromatic Protection Factor (MPF) over time, as outlined below. A
comparative composition (Example 8) was made by removing the resorcinol derivative
from the compositions in Examples 5 to 7.
Procedure for measuring MPF of cosmetic formulations
[0060] An SPF-290 Analyzer with an integrating sphere from Optometrics USA was used to acquire
the MPF data. The software generates a
Monochromatic Protection Factor (MPF) for each 5nm portion of the scan from 290nm to 400nm. The MPF is calculated from
the reciprocal of the transmission (MPF = 1/Tλ.) at each of these wavelengths (λ or
gamma). MPF is an indication of the UV protective properties of a skin composition,
since the SPF, or sun protection factor, is a weighted average of MPF values at different
wavelengths across the UV spectrum. A drop in MPF over time, therefore, indicates
loss of sunscreen activity.
[0061] The SPF-290 instrument light source is a 125 W xenon arc lamp, operated at 75W, whose
beam passes through a wire attenuator and a Schott UG05 filter. The filter attenuates
the source radiation above 500nm and alters the spectral distribution to approximate
the relative solar irradiance spectrum in the UV-B and UV-A regions. The intensity
of the beam incident on the sample is approximately 16mW/cm
2, corresponding to approximately 8 times the solar UV intensity at midday in summer
in the Northeast US. The minimum time of test site exposure to the UV beam required
for each complete scan is approximately 30 seconds.
[0062] After passing through the sample, the radiation is collected in the integrating sphere
and separated into discrete wavelength bands with an in-line Fastie-Ebert grating
monochromator optimized for UV efficiency. The bands strike the detector and generate
a signal proportional to intensity of the radiation. The MPF value at 360nm (UVA)
was used for sunscreen photo-stability evaluation in the Examples 5-8.
[0063] A UV-transparent quartz plate (10.16cm x 10.48cm x 0.32cm, 4" x 4 1/8" x1/8") was
first calibrated by placing it on the automated programmable X-Y stage and scanned
to correct for background. The product film was then applied evenly to the calibrated
quartz plate with a spatula. An 8- path wet film applicator (Paul Gardner Company,
Inc.) was used with a 7.62cm (3") path width. The applicator was manually drawn across
the plate using the 1.5 mils gap (1 mil = 0.001 inches or approximately 25 micrometers)
and the film allowed to dry for 15 minutes. The quartz plate with the product film
was then placed on the X-Y stage and scanned for the baseline measurement (t = 0).
The X-Y stage was set to scan six pre-set sites of the product film. The same six
pre-set sites were scanned every 15 minutes up to 105 minutes, while the product formulations
were stored in glass amber jars of 120ml volume at 25°C, to monitor loss of sunscreen
performance over time.
[0064] Between each measurement, the product film was removed from the UV light source and
placed in a drawer at ambient temperatures. The MPF values presented in the table
represent the average of readings from the six different sites at each time point.
TABLE 3
|
%MPF change from t=0 |
Time, min. |
Comparative, no antioxidant Example 8 |
Example 5 (with 4-ethyl resorcinol) |
Example 6 (with 4-hexyl resorcinol) |
Example 7 (with 4-hexyl resorcinol diacetate) |
0 |
0 |
0 |
0 |
0 |
15 |
-21.8 |
-3.6 |
-1.0 |
0.2 |
30 |
-23.8 |
-8.3 |
-1.7 |
1.6 |
45 |
-32.0 |
-10.1 |
-0.4 |
3.4 |
60 |
-39.0 |
-11.2 |
-1.5 |
2.7 |
75 |
-44.2 |
-14.6 |
-2.1 |
4.5 |
90 |
-48.6 |
-17.4 |
-3.8 |
-1.4 |
105 |
-51.8 |
-20.9 |
-8.3 |
-2.3 |
p-value* |
< 0.0001 |
< 0.0001 |
< 0.0001 |
< 0.0001 |
* p-values of less than 0.05 indicate statistical significance, i.e., a significant
difference between no metal oxides (Example 8) and with metal oxides (Examples 5,
6, 7). |
[0065] The results in Table 3 above demonstrate that addition of resorcinol and derivatives
to the compositions of this invention provided additional stability.
[0066] The data in the Table above was found to be statistically significant, with p-values
of less than 0.0001. The p-values were determined as follows.
[0067] Objective - Compare light blockage of the base composition of Example 8 against compositions
of Examples 5-7 containing resorcinol derivatives. The products with resorcinol additives
are expected to show a slower decrease in light blockage. The inverse of light transmission
is used as a virtual measure of light blockage.
[0068] Method - The products are applied to glass slides and six spots are measured on each slide.
There are three slides for each of the four products. This provides a total of 18
spots for each product. As is standard with studies in sunscreens, 15 minutes elapse
for drying until the first measure. Measurements are then taken every 15 minutes until
120 minutes for a total of eight time points. A mixed effects analysis of variance
will take into account the spots within slides and the correlation between time points.
[0069] The analysis of variance looks for effects of time, product and time with product
interactions. A significant time with product interaction will show if there is any
difference in the rate of change in light blockage among the products. A contrast
comparison will determine if the rate of change for the Example 8 base is significantly
different from the three products with resorcinol. Regression models for each product
will fit a function to the data for each product. The functions will assess the relationship
between time with inverse light transmission. The functions will assess the linear
effect of time.
[0070] Results - There are overall significant product, time, product with time interactions
effects with p-values less than 0.0001. The contrast shows a significant difference
of p= 0.0001 between the composition of Example 8 and the resorcinol derivative containing
compositions of Examples 5-7.
[0071] It should be understood that the specific forms of the invention herein illustrated
and described are intended to be representative only. Changes, including but not limited
to those suggested in this specification, may be made in the illustrated embodiments
without departing from the clear teachings of the disclosure. Accordingly, reference
should be made to the following appended claims in determining the full scope of the
invention.
1. A personal care composition comprising:
a. about 0.01 wt.% to about 20 wt.% of an organic sunscreen,
b. about 0.0001 wt.% to about 50 wt.% of a 4-substituted resorcinol derivative of
general formula I
wherein each R1 and R2, independently, represents a hydrogen atom, -CO-R, -COO-R, CONHR; where R represents
saturated or unsaturated, linear, branched or cyclic C1 - C18 hydrocarbon groups; and
R3 represents an alkyl group having from 1 to 18 carbon atoms or a group of the general
formula (II)
wherein X is hydrogen; OR1, wherein R1 represents hydrogen, (C1-C6)alkyl or aryl-(C1-C6)alkyl; OCOR2 wherein R2 represents (C1-C6)alkyl, aryl-(C1-C6)alkyl or phenyl; halogen; (C1-C6)alkyl; aryl-(C1-C6)alkyl, or aryl-(C1-C6)alkyl; or NHR1 wherein R1 is defined as above;
wherein n is 0 to 3 such that the structure of general formula II is a 5, 6, 7 or
8 membered ring;
wherein the dashed line indicates an optional double bond; and
c. a cosmetically acceptable carrier.
2. The composition of claim 1, wherein the organic sunscreen is selected from Benzophenone-3,
Benzophenone-4, Benzophenone-8, DEA, Methoxycinnamate, Ethyl dihydroxypropyl-PABA,
Glyceryl PABA, Homosalate, Methyl anthranilate, Octocrylene, Octyl dimethyl PABA,
Octyl methoxycinnamate (Parsol MCX), Octyl salicylate, PABA, 2-Phenylbenzimidazole-5-sulphonic
acid, TEA salicylate, 3-(4-methylbenzylidene)-camphor, Benzophenone-1, Benzophenone-2,
Benzophenone-6, Benzophenone-12, 4-Isopropyl dibenzoyl methane, Butyl methoxy dibenzoyl
methane (Parsol 1789), Etocrylene, and mixtures thereof.
3. The composition of claim 1 or claim 2, wherein the 4-substituted resorcinol derivative
is present in at least an effective amount to inhibit oxidation of the organic sunscreens.
4. The composition of claim 3, wherein the 4-substituted resorcinol derivative is present
in an amount of about 0.1 wt.% to about 5 wt.%.
5. The composition of any of the preceding claims, wherein the 4-substituted resorcinol
is selected from 4-linear alkyl resorciols, 4-branched alkyl resorcinols, 4-cycloalkyl
resorcinols, and mixtures thereof.
6. The cosmetic composition of claim 5, wherein the 4-substituted resorcinol is selected
from 4-methyl resorcinol, 4-ethyl resorcinol, 4-propyl resorcinol, 4-isopropyl resorcinol,
4-butyl resorcinol, 4-pentyl resorcinol, 4-hexyl resorcinol, 4-heptyl resorcinol,
4-octyl resorcinol, 4-nonyl resorcinol, 4-decyl resorcinol, and mixtures thereof.
7. The cosmetic composition of claim 5, wherein the 4-substituted resorcinol is selected
from 4-cyclopentyl resorcinol, 4-cyclohexyl resorcinol, 4-cycloheptyl resorcinol,
4-cyclooctyl resorcinol, and mixtures thereof.
9. The cosmetic composition of any of the preceding claims, further comprising a skin
benefit agent selected from alpha-hydroxy acids and esters, beta-hydroxy acids and
ester, polyhydroxy acids and esters, kojic acid and esters, ferulic acid and ferulate
derivatives, vanillic acid and esters, dioic acids and esters, retinol, retinal, retinyl
esters, hydroquinone, t-butyl hydroquinone, mulberry extract, licorice extract, resorcinol
derivatives, and mixtures thereof.
10. The cosmetic composition according to claim 9, wherein the skin benefit agent is
selected from alpha-hydroxy acids, beta-hydroxy acids, polyhydroxy acids, hydroquinone,
t-butyl hydroquinone, 4-substituted resorcinol derivatives, and mixtures thereof.
11. The cosmetic composition of any of the preceding claims, wherein the 4-substituted
resorcinol derivative is present as a skin lightening benefit agent.
12. A cosmetic composition comprising
a. an organic sunscreen stabilized by a 4-substituted resorcinol derivative,
b. a skin benefit agent; and
c. a cosmetically acceptable vehicle
wherein the organic sunscreen is present in an amount of about 1 wt% to about 10 wt%
of the cosmetic composition; and
wherein the weight ratio of the organic sunscreen to the 4-substituted resorcinol
derivative is about 10000:1 to about 1:10000.
13. The cosmetic composition according to claim 12, wherein the skin benefit agent is
selected from alpha-hydroxy acids, beta-hydroxy acids, polyhydroxy acids, hydroquinone,
t-butyl hydroquinone, 4-substituted resorcinol derivatives, and mixtures thereof.